Modern designs for high power and high performance RF power amplifiers, of conventional design and embodied as ICs (integrated circuits), face considerable challenges. One such challenge is the avoidance of significant reduction of energy efficiency reduction whenever output power level is adjusted to values below the peak design output power. Maintaining efficiency at various RF output power levels is an important requirement for radios that are designed to save battery power as a result of reduced power operation. Generally speaking, the power efficiency of power amplifiers operated at small signal levels will be poor unless the amplifier incorporates features expressly to remedy that incipient deficiency.
Modern designs for high power and high performance ICs (integrated circuits) RF (radio frequency) signals meet their considerable challenges by deploying any of a variety of technologies, often including out of the mainstream techniques. Dense and highly integrated designs for processing analog signals often have a very limited electrical operating range and, especially when power supply low voltages must be conformed to, such circuits may require bias currents (and/or voltages) to be controlled with great precision and robustness.
Use of the disclosed circuits and methods enables RF power amplifiers to be constructed with economy, with excellent energy efficiency thus permitting sound energy management and allowing many different power levels to be implemented thus allowing still further improvements to the energy efficiency of the total transmitter by precisely using the optimal desirable power output level.
The disclosed improved circuit designs are capable superior tradeoffs between circuit performance and cost.